Rhabdias bakeri Tkach, Kuzmin et Pulis, 2006

KUZMIN, YURIY, 2013, Review of Rhabdiasidae (Nematoda) from the Holarctic, Zootaxa 3639 (1), pp. 1-76 : 33

Rhabdias bakeri Tkach, Kuzmin et Pulis, 2006

( Fig. 15 )

Synonyms: Rhabdias ranae Walton, 1929 in Baker (1979).

Host: Lithobates pipiens , L. sylvaticus ( Amphibia: Anura : Ranidae ).

Site: lungs.

Distribution: Northern Nearctic (northern U.S.A. and southern Canada).

Description (after Tkach et al. 2006). Body 7.090 (4.051 –10.692) mm long, maximum width 245 (139–406) near vulva. Cuticular inflation less prominent in anterior part, from anterior end to level of distal part of oesophagus. In younger specimens, body cuticle evenly inflated along whole body. Oral opening oval, situated between 2 lateral pseudolabia. Each pseudolabium hemispherical in dorso-ventral view, rounded triangular in lateral view, with 2 small submedian protuberances (reduced submedian lips), each bearing a papilla. Vestibulum almost slit-like in apical view. Buccal capsule 17 (15–20) wide, 9 (7–12) deep, funnel-shaped in lateral view, round in apical view, with thick sclerotised walls. Lumen of buccal capsule narrow, cylindrical in lateral view. Anterior edge of buccal capsule slightly behind anterior edge of oesophagus. Oesophagus elongated, comparatively narrow, club-shaped, with dilated anterior muscular portion and egg-shaped posterior bulb. Oesophagus length 539 (465– 590), or 8.0 (5.4–11.9) % of body length. Width of oesophagus anterior end 36 (31–41), width of muscular dilation 43 (36–49), minimum width of glandular part 35 (27–44), width of oesophageal bulb 59 (48–72). Nerve ring encircling oesophagus posterior to its muscular dilation, at 174 (146–211) from oesophagus anterior end (32.3 [27.6–36.9] % of oesophagus length). Excretory pore opening just behind level of nerve ring. Intestine narrow at level of oesophageal-intestinal junction, then widening posteriorly. Rectum narrow, with thick sclerotised walls. Vulva postequatorial. Distance from anterior end to vulva 4.142 (2.297 –6.317) mm, or 58.7 (53.7–63.8) % of body length. Proximal ends of syngonia far overlapping at level of vulva. Egg size 50–61 × 94–113 (n = 19). Tail conical, elongated. Tail length 254 (193–336), or 3.7 (2.7–6.7) % of body length. Inflated body cuticle covering tail up to its tip in younger specimens; in older ones tail tip lacking inflated cuticle. Phasmids situated somewhat posterior to mid-length of tail.

Remarks. The species is presumably a specific parasite of L. sylvaticus occasionally parasitizing other frogs ( Tkach et al. 2006).

Material studied: 33 specimens, including the type series (17 specimens, USNPC) .

References: Baker (1978), Tkach et al. (2006).

Figures

FIGURE 15. R. bakeri. A—anterior part of body, lateral view; B—head end, lateral view; C—head end, apical view; D—tail end, lateral view. Scale bars: A, D—0.1 mm; B, C—0.05 mm.